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SWG with Automatic cover

I am in the process of designing a new pool with spa and would like to hear personal experiences with SWG and automatic covers. I love the feel of my current salt pool but would like the ease and safety of an automatic cover. I have twin 3yr old boys and want to utilize the safety of an automatic cover. I have read that chlorine can buildup under the cover but adjusting the SWG down may compensate in conjunction with being sure to have occasional time with cover open even out of swim season.

My other concern is with corrosion of the automatic cover tracks and mechanicals. I have read about the use of a sacrificial anode but would like to hear if this is an effective way to reduce the increased corrosion due to using SWG.

Re: SWG with Automatic cover

We have number of pools that we service that have automatic covers and are saltwater. Several are in the ten to twelve year old range.
All have sacrificial zinc anodes (I require this for any saltwater pool we service or retrofit).
None of these pools have exhibited any unusual problems.
I do recommend annual cleaning of the cover tracks and mechanism, and a "cover tune-up" every other year.

In the industry, CSP (Certified Service Professional) by the NSPI and it's successor the APSP. My company services over 600 pools every year. I think the practices regularly espoused on this forum (especially the BBB method) are outstanding; however my comments will be often oriented towards the goal of getting it done, and getting it done right now!

Re: SWG with Automatic cover

A sacrificial anode is a metal, usually zinc, that sort of attracts the corrosive properties of substances to itself so that the other metals that comprise the structure of the object being protected are spared. This way, the salt corrodes the zinc anode and not the metal in your pool cover mechanism.

Re: SWG with Automatic cover

it's not salt that's corrosive in this case (or at least not in a same fashion as it corrodes soft stones), it's the electron flow

basically as soon as you put salt in your pool it becomes a big electrolytic bath as salt water conducts electricity much better than fresh water.
any metal in contact with water will get corroded by the electrolysis process.

sacrificial anodes are made of the metal with more negative electropotential than the metals you are trying to protect so the electrons start flowing from them into water and from water into other metals.

Re: SWG with Automatic cover

The sacrificial anodes are best placed in moist soil so that they have a grounded "sink" for electrons to flow into. This effectively puts a positive charge on the wire they are connected to and therefore the aluminum tracks and header that compose the metal in the automatic cover. This is usually connected to the bonding wire so other metal equipment will be protected to some extent as well.

Note that an overtrack can corrode (see this post) even if you try and protect it since splash-out and evaporation can simply overwhelm them with concentrated salt (and therefore very high conductivity). An undertrack doesn't have this problem.

Re: SWG with Automatic cover

I'm a visual perrson and I'm having troublel visualizing this...... Does anyone have a picture of this? My pool is already built and is surrounded by pavers, so I'm having trouble figuring out all of the components, where they are placed, how big of the piece of Zinc needs to be, am I running something over the pavers that people will trip on,

Re: SWG with Automatic cover

See this link for examples of undertrack vs. toptrack. Undertrack is mounted under the coping overhang. This is usually done for new pools because it requires having a vault holding the reel that is below ground level and some sort of slanted tiling over which the cover goes over from the pool to the reel.

The toptrack has a track mounted on the deck (coping). You can click on any of the pictures in that link to see them in more detail.

The aluminum track/rail is electrically connected with a wire to the main reel mechanism that also is connected to the header bar at the leading edge of the cover. So the zinc block is usually connected via wire in the vault area where the reel and motor are and these are also connected to the bonding wire that connects to all of your pool equipment that has metal (conductive) contact with the water. The actual zinc block itself can be buried in moist soil anywhere in the vicinity. It does NOT sit on top of the deck or ground so there is no risk tripping over it. The only trip risk is from the track itself if it is a toptrack.